It's entirely possible that 'test' means different things for Ruby and Perl. I recently looked into what it would take to port a particular module to Ruby (because, as far as I can tell, there's no solution for parsing RTF for Ruby), and if I'd done so I would probably have had less than a tenth as many tests. The test suite for the module tested a huge number of things for no reason that I could see, such as the contents of various internal buffers during the parsing process rather than testing the output (and I'd think that that would make refactoring almost impossible....).

I'm not saying that's the case here, or that Ruby has as much test coverage as Perl, but it's entirely possible. Does it matter whether Ruby has 1 test, 1,000 tests, or 100,000 tests if they all result in the same code coverage?